Example embodiments of the present disclosure relate to an assembly for sealing a rigid pipe, a furnace, and a gasket for use in an HVAC fluid conduit. Some embodiments include a furnace with an inducer blower drawing combustion air through the furnace, and the assembly is used to connect one or more flue conduit(s) and an exhaust pipe. In one embodiment, the gasket used in the assembly includes a tubular body, at least a portion of which is engaged along an inner surface of the fluid conduit, a rim extending outwardly from a tubular body end, and two or more ears extending from the rim, wherein the ears are spaced apart from the tubular body and extend in substantially the same direction as the tubular body. The ears further include a first rib located proximate a distal end of the ear.

A method is provided for controlling combustion in a modulating gas furnace. The method includes receiving an indication of a firing rate setpoint for a burner assembly, and applying the firing rate setpoint to first and second continuous functions that map the firing rate setpoint to air-to-fuel ratio and combustion system pressure setpoints. A variable-speed draft inducer blower is set to drive to a combustion system pressure setpoint, and the modulating gas valve is controlled during combustion in the combustion system. In this regard, a combustion system pressure measurement is obtained and applied to an inverse of the first continuous function that outputs an adjusted firing rate for the combustion system pressure measurement. The adjusted firing rate is applied to a third continuous function that maps the firing rate to gas valve position, and outputs a gas valve position to which the modulating gas valve is set.

A furnace system features baffles, each set of baffles including one or more movable vanes, and systems for controlling the positioning of movable vanes during furnace operation. Actuators may be used to move vanes between deployed and retracted positions, the actuators controlled by units within the furnace or linked to the power sources for furnace elements which are specific to either heating or cooling operations. The movable vanes may alternately be positioned by using springs with stiffness selected to place vanes in a deployed position when under heating airflows and in a retracted position when under cooling airflows.

A fastening device for fluid tightly coupling a first duct body and a second duct body of a heat exchanger is provided. The fastening device includes a support member to couple with a connecting edge of the first duct body. The support member includes a pivot pin and a locking device disposed at an offset distance from the pivot pin along a radial axis of the fastening device. The fastening device further includes a pivot arm having a first end to engage with the pivot pin and a second end to engage with a flange of the second duct body. The locking device engages with the pivot arm and move the second end of the pivot arm relative to the pivot pin to fluid tightly engage the flange of the second duct body with the connecting edge of the first duct body.

An air handling apparatus for a HVAC system of a building. The air handling apparatus includes an enclosure having at least one inlet opening for drawing outside air into the enclosure, and at least one outlet opening for directing air from within the enclosure to outside the enclosure. At least one fan is mounted within the enclosure for drawing air through the enclosure. A burner box is centrally located within the enclosure for heating outside air drawn into the enclosure through the at least one inlet opening.

A portable indirect fuel fired heater includes a burner assembly having a fuel burner to deliver fuel from a fuel supply to a combustion chamber of the heater and a combustion air blower to deliver combustion air to the combustion chamber with the fuel for combustion in the combustion chamber to produce exhaust gases. A heat exchanger receives air to be heated in heat exchanging relationship with at least a portion of the combustion chamber. A sensor senses an oxygen level as a partial pressure of oxygen in the exhaust gases. A controller operates an actuator operatively connected to the burner assembly to controllably vary the delivery rate of combustion air and thus vary the ratio of the air and fuel responsive to the oxygen level sensed by the combustion sensor so as to maintain the sensed oxygen level at a prescribed set point level stored on the controller.

A PTC heating device for introduction into a receiving pocket of an electric heating device includes at least one PTC element, a conductor track that is electrically connected to the PTC element, and insulating layers that are abutted in a thermally conductive manner against the PTC element. A frame-shaped casing joins the at least one PTC element, the conductor track, and the insulating layers as a unit. The frame-shaped casing has a leading frame member with elastic guide tabs which, in an initial assembly state, project on oppositely disposed sides of the frame-shaped casing over the heat-emitting open surface respectively associated with them, which are inclined obliquely from the leading frame member in a direction of the open surface, and which are elastically pivotable. During heating device assembly, the PTC heating device is centered and guided by the elastic guide tabs when introduced into a heating rib of a heating chamber.

Embodiments of the present disclosure are directed to a furnace that includes a blower configured to operate to force a fluid through the furnace, a motor having a rated speed, in which the motor is coupled to and configured to actuate the blower, and a controller configured to receive data indicative of an operating characteristic of the furnace and regulate operation of the motor to be at or below an operational speed limit. The controller is configured to set the operational speed limit based on the data indicative of the operating characteristic of the furnace, such that the operational speed limit is less than or equal to the rated speed of the motor.

A heater having a burner, a first heat exchanger associated with the burner, a second heat exchanger above the first heat exchanger in fluid cooperation with the first heat exchanger and an ambient air intake blower above the second heat exchanger. The second heat exchanger comprises angularly disposed finned section so condensate within the second heat exchanger flows to a collection point and is collected in a trap. The trap includes a sensor to sense buildup of fluid in the trap with feedback to the heater controls. The heater may include a collection pan below the heat exchangers in fluid communication with the trap. In one aspect the collection pan may include a heating element to vaporize the fluid so that heated, humidified air is expelled through vents adjacent the base of the heater. In another aspect, the pan includes an ultrasonic vaporization element to vaporize fluid in the pan.

An air conditioner may include a casing having an inner air flow space defined therein and an entrance defined in one of a first side plate or a second side plate, a heat exchanger and a fan disposed between an outdoor air inlet body and an air outlet body in an air flow direction of the casing, a heater module inserted through the entrance into the inner air flow space, a handle mounted on one side face among both side faces of the heater module, one side face of the both side faces being closer to the entrance than the other side face thereof, a pair of guide brackets installed in the casing to slidably guide the heater module, and a door module that opens and closes the entrance. The door module may be configured to contact the handle to press the handle in a direction away from the entrance.